1. Field of the Invention
This invention relates to the field of liquid spraying apparatus and particularly to apparatus that uses a liquid-actuated motor to drive an impeller that produces a stream of air in which at least some of the same liquid supplied to the apparatus to actuate the motor is entrained in the form of finely divided particles to be driven by the air stream.
2. Prior Art
In recent years the structures of buildings and the furniture and artifacts in them have increasingly been made of polymers in place of the materials formerly used. For example, plastic outer walls are now sometimes used instead of wooden walls; plastic pipe is now used instead of some of the metal pipe that was formerly used in plumbing; some items of furniture that used to be made of wood are now made of plastic; artificial fibers are used in carpets, drapes, and clothing in place of wool and cotton; and plastic wall coatings are used in place of wallpaper. These and other plastic materials have, in differing degrees, advantages of cost, looks, ease of installation, and some other characteristics not even attainable by materials more nearly in the form in which they occur in nature. However, plastic or polymeric material frequently is seriously inferior to natural materials in the event of fire.
One of the most significant disadvantages of some plastics during combustion is that many of them release a much larger amount of smoke and highly poisonous, invisible gases than do the more traditional materials. There are, for example, polymers that produce 500 times as much smoke per pound as is produced by wood, and the poisonous gases produced by some polymers can arrest, within a few seconds, the breathing of anyone who inhales such gases and smoke.
Another serious problem is that some combusting polymers release heat 100 times as fast as wood and burn at a higher temperature than wood. This not only means that other combustible materials, whether polymers or natural materials, in the vicinity may be raised to the ignition point much more quickly than in the case of a fire fueled by burning wood, but that the fires tend to travel more rapidly. In effect, the fires flash from one point to others, and the flashing has even been known to take place between buildings separated by a thoroughfare.
Fighting such fire by streams of water from hoses, even under high pressure, is inefficient. The water does little or nothing to control the flow of smoke and poisonous gases or to limit the flashing. When the water hits a piece of burning material, the water can drown the fire by preventing further oxygen from reaching that point, and the heat in the burning object can be absorbed by raising the temperature of the water, but all of this may have no effect on other burning objects quite close to the one being struck by the stream of water. As a result, large amounts of water are used in putting out a fire, and the water damage is likely to be a significant part of the total destruction.
Fire fighters have tried using fogging devices to envelope the burning area in a fog of atomized water particles, but such fogging devices produce a force of reaction that tends to make them difficult to manage, and very dangerous to fire fighters if those who are using such devices lose hold of them. One reason that fogging devices as used heretofore have presented a special problem is that they required higher pressure to produce the fog than simply to allow the stream of water to emerge from the fire hose without change. When water emerges from the nozzle of a hose, it produces a force of reaction equal to the pressure times the outlet area of the nozzle. These factors must be kept in mind in designing a hose and nozzle and in supplying pressurized water so that the total reaction force can be managed, preferably by one fireman, if the hose is to be hand-carried. For example, if the reaction force is not to exceed about 13.5 Kg and the effective size of the output aperture of the nozzle is about 13.5 cm.sup.2, the water pressure in a hose must be limited to about 10,000 Kg/cm.sup.2, which limits the throw of water from the hose and is much smaller than the normally available water pressure. A fogging nozzle may require about twice that much pressure and thus produce about 27 Kg of reaction force, which is equal to approximately one-third of the weight of a fireman. However, the use of fog is desirable in order to blanket a burning area.
Several types of apparatus have been proposed to break up the stream of water into finely divided particles or fog or to produce a foam that, like the fog, is also capable of blanketing an area. One fog-producing nozzle is shown in U.S. Pat. No. 1,996,884 in which water from a hose is directed, by means of a divided nozzle, at opposite angles against blades projecting from a rotatable disk toward the angled nozzles. Water from the angled nozzles rotates the disk and is broken up into finely divided particles that emerge in a wide angled spray of fog from the outer end of the structure. A good deal of the force or the water is absorbed by the internal walls of the structure, which not only produces a substantial reaction force but also reduces the distance that the fog would be likely to be carried.
U.S. Pat. No. 2,968,442 describes a turbine type nozzle in which a stream of water is directed against a small propeller confined within a hollow cylinder. The water drives the propeller which, in turn, drives an electric generator. A variable resistor is connected to the generator to serve as a blade to control the speed of rotation of the propeller by loading down the generator. The water is, to some extent, broken up by striking the blades of the propeller, but the propeller does not serve to carry the water or spray along, but rather to diminish its forward movement.
U.S. Pat. No. 3,780,812 describes a structure for forming foam in front of a propeller driven by a reaction jet water powered motor. Water and a foaming agent are sprayed against a perforated member that covers the area through which a stream of air from the fan must pass. Not only is the reaction propulsion motor very inefficient, but the perforated member further slows down the stream of air, although it is necessary to have that member in the patented structure.
Other forms of blower arrangements are used to enhance the flow of oil in oil burners. One such device is shown in U.S. Pat. No. 1,055,411 in which fuel oil and air or steam under pressure are directed through a turbine and an annular channel to a diffuser at the end of the channel. The purpose of the diffuser is to assure that the oil and air are thoroughly mixed and to confine the flame to a desired region of combustion. However, it is not proposed to have the diffuser develop a stream of air of large volume per minute that would carry the liquid particles along with it, since the air only reaches the diffuser along the same constricted path as the liquid.
U.S. Pat. No. 2,276,961 also shows a reaction propulsion device which, in this instance, is used in an oil burner and is rotated by the oil emerging through reaction apertures. This structure turns a propeller that is located in the air path to help move the air along. However, the propeller cannot turn any faster than the reactive propulsion device permits. This limits its efficiency in providing a stream of air to carry particles of the fuel along.
U.S. Pat. No. 3,610,527 and its divisional U.S. Pat. No. 3,767,324 describe an atomization structure for atomizing a stream of water and entraining the atomized water in an air stream provided by a propeller mounted to rotate concentrically with and in front of the stream of water. The propeller is rotated by an electric motor, and one of the main uses of the apparatus is to make snow artificially when the temperature is low enough. The water is separated into small streams directed at the blades of the propeller to travel along the blades after striking them and fly off at the trailing edges, where they are dispersed as finely divided particles. Since the propeller blades are not driven by the water, itself, but are driven by a separate electric motor, the stream of air that they produce assists in carrying the finely divided particles a considerable distance. While this structure is suitable for making snow and for other purposes where electric power is available and where the device can be left relatively unattended, it is not suitable for use in the absence of electric power and in close proximity to people who might be injured by the swirling propeller.
It is one of the objects of the present invention to provide spraying apparatus that includes a liquid-powered motor to turn an impeller to blow a stream of air, with the same liquid that is applied to drive the motor being introduced to the stream of air to be moved along by the stream.
Another object is to provide spraying apparatus using a liquid-powered motor that utilizes the energy in pressurized water and is powerful enough to generate the necessary mechanical force to rotate an impeller capable of driving a powerful stream of air but is light enough and with small enough reaction forces to be held-hand and operated by one person.
Still another object is to provide impeller means driven by a liquid-powered motor capable of pressurizing a substantial part of a building to drive fire and combustion products along a desired path.
Still another object is to provide fire fighting apparatus in the form of a liquid-powered motor driving a fan that propels a large, fast moving stream of air in which finely divided particles of the same liquid used to power the motor are entrained from a conduit that carries the liquid to a point either behind or in front of the fan.
Still another object is to provide a liquid-powered motor to drive an impeller and to control the volume of liquid diverted from the motor to the air stream of the impeller.
A further object of the invention is to provide apparatus for spraying divided water particles a distance of approximately 15-25 meters at a rate of approximately 40 liters per minute.
Another object is to provide a positive-displacement motor suitable to be operated by pressurized water, such as from a fire hose.
Further objects will be apparent from the following specification together with the accompanying drawings.